This invention is directed to a blood-air separator for positioning in the extra-corporeal blood bypass circuits which are used in cardio-pulmonary surgery, particularly in the arterial bloodstream just before it reenters the body.
It is necessary to separate gas bubbles, usually air bubbles, from the arterial bloodstream before the stream returns to the patient. Air embolism can quickly cause death. The blood filters which are sometimes used in the extra-corporeal blood bypass circuit tend to filter out air bubbles because the air bubbles do not readily pass through the blood-wetted filter element. However, from the surface of the filter element, it is hard to permit the bubbles to rise and accumulate in the top of the filter housing so that they can be separated. In conventional filters, some bubbles can be seen to circulate for quite a while, and it is difficult to capture them or permit them to accumulate in the top of the filter because of turbulence of many small bubbles. The prior art filters, except the blood filter described in the above-identified parent application, are not well-designed for the removal of air from the arterial bloodstream. Thus, there is need for a structure which readily and reliably removes air bubbles from the bloodstream.